I recently came upon the following website which list a few handy and to the point useful tools for the Internet: addr.tools

INDEX

challenges.addr.tools dns-01 ACME challenge helper zone

dyn.addr.tools simple dynamic DNS for your own domains, no account required

header-echo.addr.tools view HTTP request headers, craft HTTP response headers

info.addr.tools explore identifying information for domain names and IP addresses

ip.addr.tools construct domain names that resolve to any given IP address

myip.addr.tools get your public IP address

dnscheck.tools identifies your DNS resolvers, checks DNSSEC validation, and more

myaddr.tools yet another dynamic DNS service, custom names included